1)
What is the significance of "Kol Kanfei ha'Keruvim"?
1.
Malbim: Refer to 1:24:1:1. The voice was the command that came via them to lower beings.
2)
What is "ha'Chatzer ha'Chitzonah"?
1.
Rashi: It is Har ha'Bayis.
3)
Why was the voice not heard past the Chatzer?
1.
Rashi: It is not because it was low - it was "k'Kol Kel Shakai"! Rather, the voice ceased there.